Clean install with home folder and multiple users

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I had reformatted my system (unfortunately an update failed) and had my home folder on a separate partition. Thankfully I still have all of my users files (in their respective folders), but there was no option to use this on install (since my update had failed...).
How can I recreate the old users with their previous home directories?
(Are there problems with user permissions with just dragging and dropping the entire contents of folders?)
(HowTos)

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I amm moving stuff out of a file Server. I am using DFS for that - the Folders are anyway in a DFS tree, so I can set up a replication temporarily, then drop the old Folder. Works nice, EXCEPT for the Folder containing the users home drives. Which, incidentally, is also the one I can not see all files in due to my permissions.